Table 3.

Studies exploring respiratory infections or studies exploring wheezing in the context of respiratory infections

	Age at gut microbiota determination	Diversity (respiratory disease vs non-respiratory disease)	Relative abundance of bacteria taxa (fungal taxa) in respiratory disease versus non-respiratory disease	Age of participants at respiratory disease determination (outcome)	AHRQ rating
Reyman et al (2019)33	≤1 month	Not reported	Lower Bifidobacterium; higher Klebsiella and Enterococcus	1 year (cumulative incidence of respiratory infections)	Good
Arrieta et al (2015)27	3 months	No difference	No difference	1 year (wheezing)	Poor
Boutin et al (2020)35	3 months	α-diversity decreased	Lower Faecalibacterium, Lachnospira, Coprococcus, and Oscillospira	1 year (recurrent wheezing)	Poor
Laursen et al (2015)28	9 months	No difference	No difference	3 years (wheezing in respiratory infection context)	Poor
Arrieta et al (2015)27	1 year	No difference	No difference	1 year (wheezing)	Poor

AHRQ=Newcastle-Ottawa Quality assessment for cohort and case-control studies converted to the Agency for Healthcare Research and Quality scale.